cat2

$ time cat linux-4.14.2.tar >new

real    0m0,296s
user    0m0,004s
sys     0m0,291s
$ time cat linux-4.14.2.tar >new

real    0m0,297s
user    0m0,004s
sys     0m0,293s
$ time cat linux-4.14.2.tar >new

real    0m0,306s
user    0m0,000s
sys     0m0,306s
$ time cat linux-4.14.2.tar >new

real    0m0,293s
user    0m0,000s
sys     0m0,292s
$ time cat linux-4.14.2.tar >new

real    0m0,299s
user    0m0,000s
sys     0m0,299s
$ time cat linux-4.14.2.tar >new

real    0m0,296s
user    0m0,000s
sys     0m0,295s
$ time cat2 linux-4.14.2.tar >new

real    0m0,265s
user    0m0,000s
sys     0m0,265s
$ time cat2 linux-4.14.2.tar >new

real    0m0,266s
user    0m0,000s
sys     0m0,265s
$ time cat2 linux-4.14.2.tar >new

real    0m0,273s
user    0m0,000s
sys     0m0,274s
$ time cat2 linux-4.14.2.tar >new

real    0m0,265s
user    0m0,000s
sys     0m0,265s
$ time cat2 linux-4.14.2.tar >new

real    0m0,265s
user    0m0,000s
sys     0m0,265s
$ time cat2 linux-4.14.2.tar >new

real    0m0,268s
user    0m0,000s
sys     0m0,268s

$ strace cat linux-4.14.2.tar 2>&1 >new |wc -l
12630

$ strace cat2 linux-4.14.2.tar 2>&1 >new |wc -l
42

diff --git a/src/cat.c b/src/cat.c
index a3680a3fc..06cf7a2bc 100644
--- a/src/cat.c
+++ b/src/cat.c
@@ -32,6 +32,10 @@
 #endif
 #include <sys/ioctl.h>

+#ifdef __linux__
+# include <sys/sendfile.h>
+#endif
+
 #include "system.h"
 #include "ioblksize.h"
 #include "die.h"
@@ -157,13 +161,21 @@ simple_cat (
         call.  */
      size_t bufsize)
 {
-  /* Actual number of characters read, and therefore written.  */
-  size_t n_read;
-
   /* Loop until the end of the file.  */

   while (true)
     {
+#ifdef __linux__
+      /* maximum size transferred by sendfile() as in manpage */
+      ssize_t xfer = sendfile(STDOUT_FILENO, input_desc, NULL, 0x7ffff000);
+      if (xfer == -1)
+        return false;
+      if (xfer < 0x7ffff000)
+        return true;
+#else
+      /* Actual number of characters read, and therefore written.  */
+      size_t n_read;
+
       /* Read a block of input.  */

       n_read = safe_read (input_desc, buf, bufsize);
@@ -186,6 +198,7 @@ simple_cat (
         if (full_write (STDOUT_FILENO, buf, n) != n)
           die (EXIT_FAILURE, errno, _("write error"));
       }
+#endif
     }
 }